clear all;
close all;
%定義鎖相環(huán)的工作模式：?jiǎn)屋d波為“1”、BPSK調(diào)制為“2”、QPSK調(diào)制為“3”
PLL_Mode = 3;
%仿真數(shù)據(jù)長(zhǎng)度
Simulation_Length=1000;
%基帶信號(hào)
if PLL_Mode == 1
I_Data=ones(Simulation_Length,1);
Q_Data=I_Data;
else if PLL_Mode == 2
I_Data=randint(Simulation_Length,1)*2-1;
Q_Data=zeros(Simulation_Length,1);
else
I_Data=randint(Simulation_Length,1)*2-1;
Q_Data=randint(Simulation_Length,1)*2-1;
end
end
Signal_Source=I_Data + j*Q_Data;
%載波信號(hào)
Freq_Sample=2400;%采樣率，Hz
Delta_Freq=-80; %頻偏，Hz
Time_Sample=1/Freq_Sample;
Delta_Phase=rand(1)*2*pi; %隨機(jī)初相，Rad
Carrier=exp(j*(Delta_Freq/Freq_Sample*(1:Simulation_Length)+Delta_Phase));
%調(diào)制處理
Signal_Channel=Signal_Source.*Carrier';
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%以下為鎖相環(huán)處理過程
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%參數(shù)清零
Signal_PLL=zeros(Simulation_Length,1);
NCO_Phase = zeros(Simulation_Length,1);
Discriminator_Out=zeros(Simulation_Length,1);
Freq_Control=zeros(Simulation_Length,1);
PLL_Phase_Part=zeros(Simulation_Length,1);
PLL_Freq_Part=zeros(Simulation_Length,1);
%環(huán)路處理
C1=0.022;
C2=0.0010;
for i=2:Simulation_Length
Signal_PLL(i)=Signal_Channel(i)*exp(-j*mod(NCO_Phase(i-1),2*pi));
I_PLL(i)=real(Signal_PLL(i));
Q_PLL(i)=imag(Signal_PLL(i));
if PLL_Mode == 1
Discriminator_Out(i)=atan2(Q_PLL(i),I_PLL(i));
else if PLL_Mode == 2
Discriminator_Out(i)=sign(I_PLL(i))*Q_PLL(i)/abs(Signal_PLL(i));
else
Discriminator_Out(i)=(sign(I_PLL(i))*Q_PLL(i)-sign(Q_PLL(i))*I_PLL(i))...
/(sqrt(2)*abs(Signal_PLL(i)));
end
end
PLL_Phase_Part(i)=Discriminator_Out(i)*C1;
Freq_Control(i)=PLL_Phase_Part(i)+PLL_Freq_Part(i-1);
PLL_Freq_Part(i)=Discriminator_Out(i)*C2+PLL_Freq_Part(i-1);
NCO_Phase(i)=NCO_Phase(i-1)+Freq_Control(i);
end
%畫圖顯示結(jié)果
figure
subplot(2,2,1)
plot(-PLL_Freq_Part(2:Simulation_Length)*Freq_Sample);
grid on;
title('鎖相環(huán)頻率響應(yīng)曲線');
axis([1 Simulation_Length -100 100]);
subplot(2,2,2)
plot(PLL_Phase_Part(2:Simulation_Length)*180/pi);
title('鎖相環(huán)相位響應(yīng)曲線');
axis([1 Simulation_Length -2 2]);
grid on;
%設(shè)定顯示范圍
Show_D=300; %起始位置
Show_U=900; %終止位置
Show_Length=Show_U-Show_D;
subplot(2,2,3)
plot(Signal_Channel(Show_D:Show_U),'*');
title('進(jìn)入鎖相環(huán)的數(shù)據(jù)星座圖');
axis([-2 2 -2 2]);
grid on;
hold on;
subplot(2,2,3)
plot(Signal_PLL(Show_D:Show_U),'r*');
grid on;
subplot(2,2,4)
plot(Signal_PLL(Show_D:Show_U),'r*');
title('鎖相環(huán)鎖定及穩(wěn)定后的數(shù)據(jù)星座圖');
axis([-2 2 -2 2]);
grid on;

figure
%設(shè)定顯示范圍
Show_D=300; %起始位置
Show_U=350; %終止位置
Show_Length=Show_U-Show_D;
subplot(2,2,1)
plot(I_Data(Show_D:Show_U));
grid on;
title('I路信息數(shù)據(jù)');
axis([1 Show_Length -2 2]);
subplot(2,2,2)
plot(Q_Data(Show_D:Show_U));
grid on;
title('Q路信息數(shù)據(jù)');
axis([1 Show_Length -2 2]);
subplot(2,2,3)
plot(I_PLL(Show_D:Show_U));
grid on;
title('鎖相環(huán)輸出I路信息數(shù)據(jù)');
axis([1 Show_Length -2 2]);
subplot(2,2,4)
plot(Q_PLL(Show_D:Show_U));
grid on;
title('鎖相環(huán)輸出Q路信息數(shù)據(jù)');
axis([1 Show_Length -2 2]);